Getting 'insertItemAt is not a function' Error Message

Question

I am using abode pro 8 and am getting a 'insertItemAt is not a function' error message using the following code. (This code below was written as an example to show the process I want - I want to clear a combo box, then add data to it.)
The error message only appear in a one of my pdf's I currently use, otherwise it works as written. Because I want the data to appear listed from top to bottom within the combo box from 1 to 5, I insert 5 first. 5 gets inserted, but when the code tries to insert 4, it trippers the error message. Any thoughts - is there another way to insert data into a combo box?
var i = 0;
var ii = 5;
var v = new Array();
v[1] = 1;
v[2] = 2;
v[3] = 3;
v[4] = 4;
v[5] = 5;
//Combo Box
this.getField("Fund Company-Long-Name").clearItems();
var a = this.getField("Fund Company-Long-Name");
for (var i= ii;  i > 0; i--)
             if(v[i] != undefined)
                         app.alert(i);      
                         a.insertItemAt(v[i], (i, ""));
v[0] = " ";
a.insertItemAt(v[0], (0, ""));
this.getField("Fund Company-Long-Name").value = " ";  
//================Gives this error message=============
Acrobat Database Connectivity Built-in Functions Version 8.0
Acrobat EScript Built-in Functions Version 8.0
Acrobat Annotations / Collaboration Built-in Functions Version 8.0
Acrobat Annotations / Collaboration Built-in Wizard Functions Version 8.0
Acrobat Multimedia Version 8.0
Acrobat SOAP 8.0
a.insertItemAt is not a function
4:Field:Mouse Down

Answer 1

Yes, I'm actually looking at those two methods now. New questions arise.
If my combo Box is called "Fund Company-Long-Name", how could I add a varying number of items to it, using the "setItems" command?
I can get it to work for a defined number of items, as below. But I don't know how to insert a variable to replace ["A", "B", "C"] below.
/=======================================
this.getField("Fund Company-Long-Name").clearItems();
var a = this.getField("Fund Company-Long-Name");
a.setItems(["A", "B", "C"]);